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The Russian
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Discussion Starter #1
Trying to do some research before buying one:

1. Which shaft? The tubes on the boat are 22", so would a shaft of 20" work or do I need to go with a 25" ultra long shaft?
2. How to store a 4 stroke motor? Prop it on it's bracket and throw a line around it or do I need to store it somewhere else during rapids? (Class 3-4)
3. Does anyone have any experience with Tohatsu/Nissan motors? Tohatsu Outboards 6 Horsepower
4. Any other suggestions are welcome, a total motor newbie here.

Thanks,
Alex
 

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How are you planning on mounting? A bracket off the end of a round boat? On the frame of a cat? Between 2 round boats? That affects size and storage. The little I've done with motors on round boats, they've always been stowed in a drop hatch during rapids. One of these days I'll get a motor for my cat, and I think it will be okay just propped up but I haven't tried it yet.

Curious what other people think.
 

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Funny, Alex, I just recently started doing research on this as well... please keep us updated on what you find out.

Has anyone ever tried mounting a motor off the side of the raft... it wouldn't be pushing in line exactly, but I've seen this done on alum boats before.

DanCan
 

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Boy Howdy!
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Jeez, last weekends wind event has alot of people thinking about motors. I plan on making a removable transom that will attatch to my frame with the same aluminum i used to buil the frame and t fittings
 

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Herdsire

I would recomend the Yamaha lightweight series in either the 4hp or 6hp models for your application. I fish about 100 days a year have had excellent performance with every Yamaha I have had on my fishing boat.
Both the 4hps and the 6hp have built in fuel tanks which would eliminate the need for a seperate fuel tank and a troublesome fuel hose. A seperate good quality fuel can would be much less prone to any spills and much easier to store onboard your raft. Both models weigh about 60lbs and are one cylinder. One draw back to the single cylinder is they tend to have more vibration than the 2 cylinders.
Honda also makes excellent outboards but they tend to be quite a bit heavier but are excellent motors.
Regarding the shaft length, I would depend on the height of the motor mount. Any good outboard dealership could give you advice on the length of shaft you will need on the motor. Both my motors stay on the back of my fishing boat so I can't offer any advice on the storage issue, but I would also ask the dealer about the proper position to store the motor.
There is nothing worse than having to deal with motor problems when your boating. My best advice is to spend the extra money and buy a good brand to start with. They tend to have a much better resale value as well.
 

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I'd give a little thought to a Diesel outboard.

I used to have a 10 hp Tohatsu on a fishing boat and that little motor was the shiz-nit.

It got really good fuel economy (compared to a 2 stroke) and was much quieter than most outboards.

Diesel also makes good sense on the river - far less likely to explode into a giant fire ball

Diesel outboards run a bit more than comparable gasoline models, but based on my experiences they require less maintenance, burn less fuel, and last longer.

Something to consider...
 

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*edit* I just looked over Tohatsu's site and it appears they no longer make Diesels, or at least I wasn't able to find any.

Just the same I'd do some research on Diesel outboards, I wish I'd never gotten rid of mine.
 

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Has anyone ever tried mounting a motor off the side of the raft... it wouldn't be pushing in line exactly, but I've seen this done on alum boats before.

DanCan
Not going to work well at all
Rafts already aren't effecient for motoring because of the shape of the bottom. There's much MUCH more resistance on the bottom of a raft when compared to pretty much any aluminum boat. SB rafts will be worse than bucket boats, but niether is made to track like an alum boat.

If that resistance is beside the engine the boat will want to run in circles. Yes, it already does with an aluminum boat, but that will also have a relatively smooth bottom, maybe with a keel for better tracking.
 

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Boof like a Utard.
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tohatsu 6hp

I have a Maravia raft with 20" tubes, and I just bought a tohatsu 4 stroke, 6hp with a 20" shaft. I'm a motor newbie as well. I bought the one with an integrated fuel tank for 1-day westwaters. There is a fuel valve and place to connect a larger, separate tank as well. The motor weighs about 60 pounds. My transom setup is what people call a 'ladder' transom. It's a pair of bars going straight off the middle of my frame and over the stern. The mounting bracket is an aluminum plate with a double stack of 1 x 6" trexx. Unfortunately I don't have any pictures yet, but my plan is to rig the motor onto the transom bars during rapids. The place where I bought my motor (they are a Nissan and Tohatsu dealer) said the only difference between Nissan and Tohatsu is the decal on the cowling (and the price). I have been told that Tohatsu also makes the smaller Mercury 4 stroke engines (up to around 40 hp). Basically I paid around $1200, but would have paid around $1400 for a Nissan, and around $1700 for a Mercury. I love the motor and will get some pics up when a small upgrade is made to my transom. My transom was made by Eddyline Welding here in Moab.
 

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Boof like a Utard.
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I have a Maravia Williwaw I, which has 20" tubes all the way around. The 20" shaft does fine. Tohatsu suggests that the cavitation plate on the motor be only 2" below the bottom of the boat and the weight of the motor itself sags the tubes that low. Sometimes I have to sit on the transom to get the prop to bite when accelerating, but once the prop is loaded it does just fine. You can also adjust the trim of the motor at the transom bracket which raises/lowers the prop by moving a pin. It also helps that my raft is older and is often alittle soft.
 

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The Russian
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Discussion Starter #13
Tohatsu sells 25" shaft, do you think it would be too long? It's going on a Maravia 16' with 22" tubes, fairly new boat.

Have you had any issues with the motor? Can you take a pic of your transom?
 

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Boof like a Utard.
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kazak:

I think the 20" shaft would likely be ok. You can have the transom designed so that the height of the mounting boards are adjustable. I'm sure Eddyline Welding could do an adjustable transom. Regardless of how new/hard your tubes are, the prop will push the tube down when you give it throttle. I think having less lower unit in the water is better than more. Also consider that your boat doesn't float on the very bottom of the tubes, especially with passengers, oars, coolers, boxes, and dunnage. In other words your boat, even with 22" tubes, draws some water. The weight of the motor will help submerge your tube as well. If you know someone near where you live who has a motor, you could give them a call and see what their setup looks like. I'm not blowing you off; I'm just new at this too and a second (and more experienced) opinion couldn't hurt. I'll put up a few pictures once I get my transom back, which will hopefully be tomorrow.
 

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For uses like westy, consider a home made transom that goes between the sterns of 2 boats. we mounted one to an oar shaft after the ranger nixed the motor mount due to lack of boat registration. it worked well enough. The motor was stashed in a separate boat.

I've run a small motor off the side of one boat this was as well. you waste some energy going diagonally, but it certainly works.

Motor mounts require tinkering and tuning to get the height right. An adjustable transom is best. Get creative with the remote, so you don't have to sit by it.
 

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Hi,

The transom I made for my 14' NRS SB a few years ago consists of 2 pieces of galvanized tubing that I paid an electrical shop $10 to bend, and two pieces of plywood. The inside diameter of the tubing accepts standard NRS fittings, which attach to the rear-most crossbar of the frame. When the motor was off the transom, I lashed it to the two plywood cross-pieces. Cheap, but effective.

The first version of the sliding mount device that Alvin used at WW -- before the current one -- was made from two garage door tracks with aluminum bracing holding the tracks apart about 16". The plywood transom slid on the same rollers that garage doors roll on. Crude, but effective, in that you could travel with the motor up and then deploy it in about one minute without a whole lot of physical effort.

However, as someone has noted, this kind of setup takes up quite a bit of space in the rear of the boat. You can store gear under and around these gizmos, but then you have to remove it all to get to the motor and operate it.

FWIW.

Rich Phillips
 

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I have an ultra long shaft Nissan 4 stroke 6 horse motor with a rock hopper. Tohatsu makes most of the small ultra long shaft motors classified as sail boat motors including mine. If you are going to buy new, buy ultra long shaft. I primarily use mine mounted on my dory. But, I also use it on my 15'6" Aire with NRS's transom. The NRS transom works well for the price, but there are certainly better designs. A long shaft works fine for 16' series rafts but, if you pick up an 18' the ultra long shaft works better. Also, a rock hopper pays for its self pretty quick, since minimal loss of propulsion isn't a big deal for this paticular application. Marc
 

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Boof like a Utard.
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I forgot the mention the skag guard on the bottom of my motor. Marc got it right when he said those pay for themselves. The one I have is called the Mac's River Runner and I've already smacked a couple rocks with it. It's worth the money.
 

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Setting up a new motor mount as well. Raft is a 16' Maravia Mistral with 22" tubes. Lots of bow/stern rise. Got the Caimbridge Motor mount thinking the tube stiffness will handle the motors torque. Here are a couple photos with a measuring tape from the trailer deck to transom mount. Granted the motor will weigh down the tube and its on a trailer, not the water. I think a long shaft will be needed for sure.


 
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